int main()
{
    int x=3;
    const int y=4;

    printf("&x=%x &y=%x\n",&x,&y);
    int *p=&x;
    ++*p;
    printf("x=%d y=%d\n",x,y);
    p[-1]++;
    printf("x=%d y=%d\n",x,y);


    return 0;
}
